Northern Spire

The Northern Spire comprised the design and construction of a new cable-stayed dual carriageway bridge over the River Wear in Sunderland, United Kingdom.

Division(s)

Europe Materials

Business Type(s)

Paving & Construction

Location

Sunderland, United Kingdom

The challenge

Multiple challenges were faced in the construction of this project. One was its location on an industrial site on the south bank of the River Wear, spanning a Site of Nature Conservation Interest. This meant that environmental considerations were key, including minimising the impact on migratory fish and mitigating any habitat loss caused by the bridge’s foundations.

Key technical challenges included the transportation and installation of the 105m pylon, in particular the connection of the hinge at the base of the pylon to the in-river foundations.

The high level of architectural excellence incorporated into the design presented further challenges. The pylon incorporates specially made steel plates that are curved in two directions to form the ‘hips’ of the pylon and the concrete ‘tusks’ that rise out of the water. These were formed in bespoke steel shutters, which were angled to the vertical and tapered in two directions.

The solution

Construction of the bridge was a Joint Venture partnership between Farrans, A CRH Company, and Belgian steel construction specialist, Victor Buyck. Together they built a supply chain made up of local and international teams carrying out activities on site, nationally and abroad, all working collaboratively.

The 105m tall and 1,500 tonne A-frame was fabricated offsite in factory conditions in Belgium and delivered to site via sea. The pylon was connected to two tusk-like RC structures built into the riverbed foundations which supported the A-frame in its final position. A temporary back mast was attached to the A-frame and connected to four stand jacks anchored 30m into the ground. Together they pulled the pylon into position through 90o over a 16-hour period.

Transporting the pylon from its fabrication base in Belgium to the site in Sunderland was a challenging operation, due to low bridges along the canal system in Belgium, busy shipping lanes across the North Sea, and the shallow depths and twists and turns of the River Wear. Three separate barges were used, each designed to address specific challenges posed by the different phases of the route.

The bridge deck was assembled in two parts on site in Sunderland, allowing the construction team to maximise use of the small assembly area available. Both sections were ‘launched’ across the river to create the 330m deck. The work was akin to threading a needle, as the deck was inched accurately through the pylon to reach the north bank.

Ongoing consultation and communication with external stakeholders ensured effective solutions were found to minimise environmental impacts, including on the migratory fish.

The outcome

Northern Spire is the first new bridge to be built across the River Wear in Sunderland for 40 years, and the innovative construction method used achieved the “landmark statement” steel frame bridge that the client wanted. The project was delivered on time and within budget, with no lost-time incidents during 1,000,000 man hours of construction and minimal environmental impact.